1. Field of the Invention
This invention generally relates to a polysulfone composition useful for coating an implantable device such as a drug eluting stent.
2. Description of the Background
Blood vessel occlusions are commonly treated by mechanically enhancing blood flow in the affected vessels, such as by employing a stent. Stents are used not only for mechanical intervention but also as vehicles for providing biological therapy. To effect a controlled delivery of an active agent in stent medication, the stent can be coated with a biocompatible polymeric coating. The biocompatible polymeric coating can function either as a permeable layer or a carrier to allow a controlled delivery of the agent.
Polymeric coatings for delivery of therapeutic agents on implantable devices, e.g., drug-eluting stents, often suffer from poor mechanical properties, poor surface properties and poor biocompatibility. A coating on a stent with such shortcomings would be unsatisfactory for use in a patient. For example, a stent with poor biocompatibility may illicit undesirable immuno reactions from the patient, and a stent with poor surface properties may not be effective in controlling release rate of an agent in the coating. Therefore, there is a need for polymeric coating compositions that provide coatings with balanced mechanical properties, optimal permeability and good biocompatibility.
The polymer and methods of making the polymer disclosed herein address the above described problems and needs.